1. Field of the Invention
The present invention relates to pentaerythritol derivatives represented by the following formula 1, which improve the moisture retaining ability of the stratum corneum when applied to the skin, and especially show high moisturizing ability even in dry conditions, to a preparation method thereof, and to a liquid crystal base containing the same.

(Wherein R is the same or different, saturated or unsaturated, linear or branched alkyl groups of 1 to 24 carbon atoms having hydrogen or hydroxy group or not; m and n are the same or different integers of which m is 0 to 10 and n is 1 to 10).
2. Description of Prior Art
The stratum corneum of the skin has the functions of protecting the human body from external harmful substances, and preventing moisture inside the skin from evaporating outside, thereby maintaining skin moistness. However, as the skin becomes aged, these functions of the stratum corneum deteriorate and the skin becomes easily dry. Moreover this tendency is increased in dry winter conditions.
Therefore, in order to improve skin dryness, numerous moisturizers have been developed. Representative examples are water-soluble moisturizers and ceramides. Because water-soluble moisturizers such as amino acid, organic acid and urea have excellent water absorbing ability, and provide moisture for the stratum corneum layer, they are used as general moisturizers. However, they show the problem that moisturizing ability decreases drastically in dry conditions of low humidity such as in winter. Further, although ceramides, as important constituents of intercellular lipid in the stratum corneum cells, have an excellent effect on enhancing skin barrier function and maintaining skin moisture, their stability of formulation decreases when used in high content because they have low compatibility with oils used in cosmetic compositions. Therefore, ceramides have been difficult to use in substantially effective concentration.
Therefore, there is a need to develop oil-soluble moisturizers that have high moisturizing ability, thus having an excellent effect on moisture maintenance even in dry conditions, and also being easy to use in cosmetic compositions.
The present inventors have studied to develop oil-soluble moisturizers, and as a result, have developed pentaerythritol derivatives represented by the following formula 1, which show high moisturizing ability even in dry conditions, to complete the present invention.